The St. Louis cut (also known as the Kansas City or SLC cut) takes a side of ribs minus the chine bone (the connector that goes to the spine of the animal) and reduces it to a squared-off rack and a meaty strip of ends. (Conveniently, the squared shape of the rack of ribs fits cleanly into the smoker.)

ready for trimming (photo by wm. christman)

The first few cuts are more clean-up ones that involve trimming stuff on the bone side (the side that faces in to the inner cavity of the pig). You'll be removing a flap of meat and stripping the membrane that hugs the ribs on that side.

the flap of meat on the bone side will vary from one inch to nearly three inches on healthy sized hogs (photo by wm. christman)

The flap cut is easy. You just run your knife parallel to the surface of the ribs to remove it. Lifting it as you cut takes it off easily and cleanly.

cut parallel to the bone side (you can see the pleura just below the knife) (photo by wm. christman)

Next is probably the biggest pain in the butt with this cut: removing the pleura (membrane) from the bone side. The pleura is tough and very difficult to chew and for those reasons alone, you want to remove it. It also contracts when heated and will cause your rack of ribs to develop the equivalent of culinary scoliosis.

I usually use a strong bamboo chopstick and a kitchen towel to loosen and remove the pleura. (You can also use a paring knife to ease the pleura away from the bones.) Using a shallow poking motion, you ease the chopstick underneath a piece of the pleura near the short end of the rack - this may take a few attempts, it can be pretty slippery and tough.

Once you get underneath a piece of it, wiggle the chopstick back-and-forth horizontally until you start to lift the pleura away from two or three of the small ribs. When it starts to lift off the bones, the pleura will make a slight sucking sound, not unlike slurping coffee.

working the pleura up and away (photo by wm. christman)

Once you've got it separated like this, grab a kitchen towel, wrap it around your fingers and work it under the separated pleura. Then use the towel to rip it off in one long strip. In a meat processing plant, the action of breaking down the primals that make up the ribs will nick the pleura and it won't come off in one clean piece. Just repeat the chopstick poke and wiggle then towel rip until you get most of the pleura off.

The rest of the St. Louis cut is easy. Turn the rack meat side up so that the curved edge is at the top of your cutting board. The tops of the rib bones are about 1/3 the way down from the top edge of the ribs. Feel around on one side to see where they begin.

running along the top of the bone and though the cartilage (photo by wm. christman)

The slightly deceptive thing about this is that nestled up against the tops of the bones are equally vertical pieces of cartilage that extend close to the top edge. Just put the edge of your knife where it seems less hard and start to make a horizontal cut along the top. Then with downward pressure, pull your knife in a straight line through the meat and cartilage. It is generally good to leave a piece of the cartilage in the finished rack so don't too close to the top edge of the bone. You can always trim more off if you need to.

the finished St. Louis cut with ends and scrap (photo by wm. christman)

Then trim up the vertical ends to square off the rack. When you're done, you should have a nicely shaped St. Louis rack, a thick set of rib "ends" and few random scraps to add to the pork stock bone bin (pork stock makes a great base for barbecue sauce, by the way...).

Rub them up (and the ends too!) with your favorite spices or just use coarse salt and pepper, let them rest a few hours or overnight in the refrigerator then get them to the smoker for a couple of hours of quality time in the smoke.